...ISS hardware associated with Node 3 is suffering from issues during proof testing on the ground.

"It looks like we are just not catching a break. Today while proof testing one of the new flight unit ammonia lines there was another rupture," noted a memo from ISS Flight Director (STS-130 Orbit 2 FD) Robert Dempsey late on Thursday night acquired by [NASASpaceflight]...

"Due to the history, options could be a full redesign, a tweak, a new vendor -- which would mean a slip to the nominal mission timeline. As you might expect, [ISS Program Manager Mike] Suffredini wants us to assess the impact to performing a modified mission where we just install the Node 3 and hook up the LTA (Launch To Activation) cables.

"We will also consider swapping the order of the missions."

Strategy meetings will take place throughout Friday with the ultimate aim to have options on the table by next Tuesday.

...but a delay is far from certain. Engineers said it may be possible to clear the lines for use as is, allowing Endeavour's crew to take off on time. If the lines can't be used, NASA could opt to launch the new module on time but delay its activation until new lines can be installed during a subsequent flight.

Sources said senior managers have ruled out delaying Endeavour's launching until after a flight currently scheduled for mid March.

...NASA managers originally intended to attach Tranquility to Unity's Earth-facing port but later decided to mount it on the left side instead. Connectors needed to circulate ammonia coolant to and from Tranquility were not correctly positioned, or "clocked," for Tranquility to be attached to Unity's left-side port.

As a result, custom hoses were ordered to compensate for the offset. During a ground test this week, a hose ruptured below the expected threshold. The failure occurred at a much higher than normal pressure, but engineers are looking into the issue to find out what might be needed to resolve the matter.

Additional testing may show the hoses are acceptable for flight as is, a manager told CBS News. If not, engineers also are considering whether Tranquility can be launched on time, delaying its activation and connecting "keep-alive" power until new or redesigned hoses can be launched and installed during a later flight.

Space station engineers and managers plan to discuss the issue in more detail Tuesday.

"Folks are working really hard to get the hoses checked out, completed, certified [and] tested," said Pete Hasbrook, NASA manager for the Expedition 22 mission aboard the space station. "We are still working toward the Feb. 7 launch date."

...Hasbrook said station engineers have successfully tested a "beefed up" version of the coolant hoses using an extra layer of braided metal in Florida, though the final approval on the repair is still under review. Meanwhile, another team at the Marshall Space Flight Center in Huntsville, Ala., is working to modify spare station hoses to replace the damaged ones in case they don't pass muster, he added.

Still another option is to launch Endeavour and the Tranquility module as planned, but to delay the space room's full activation until March or later, when new hoses could be launched on a different shuttle flight, Hasbrook said.

NASA managers decided Tuesday to modify existing space station ammonia coolant hoses by welding shorter sections together to replace a longer hose design that failed a recent ground pressure test. If the work goes well - and the schedule is tight - NASA hopes to launch the shuttle Endeavour on Feb. 7 as planned to deliver a new module to the orbiting lab complex.

...At a space station program requirements control board meeting Tuesday at the Johnson Space Center in Houston, NASA managers decided to replace the suspect hoses with shorter, flight-qualified lines that will be welded together to reach the required length.

At the same time, engineers will modify the hose design that failed in an attempt to make it strong enough to meet the design criteria. Those hoses will be used as backups.

NASA spokesman Kelly Humphries said the welded hoses and the modified longer lines are expected to be shipped to the Kennedy Space Center about five days before Endeavour's planned launching.

"Both sets of hoses are expected to be ready within a day or so of each other," he said.

Robert Pearlman

NASA update

NASA managers weighed all options and have decided to continue working toward a Feb. 7 launch with full mission content. A decision was made to select an alternate hose design, assembled from shorter hoses that were previously certified and tested, for use aboard the station as the primary jumper.

Also, managers decided on the accelerated development of a redesigned set of hoses, based on the design that failed, for use in the event a problem arises with the new primary design. Discussions were discontinued related to partial activation of the Tranquility module‪.